/Engine/Source/Runtime/Foliage/Public/ProceduralFoliageSpawner.h
Returns the instances that need to spawn for a given min,max region
void GetInstancesToSpawn ( [TArray](API\Runtime\Core\Containers\TArray)< [FProceduralFoliageInstance](API\Runtime\Foliage\FProceduralFoliageInstance) > & OutInstances, const FVector & Min, const FVector & Max ) const